New research has found that babies who have older siblings are at a greater risk of serious illness from influenza.
Babies and toddlers with at least one older sibling were more than twice as likely to be hospitalised with flu, and three times more likely if they have more than one older brother or sister.
As the flu vaccine is not suitable for babies under six months, parents are being urged to vaccinate older children to protect the youngest family members.
Catching the flu can have serious repercussions for babies as they can develop breathing difficulties, lung infections and a high fever which can result in a fit.
This study examined data from health and birth records of 400,000 children born in Scotland between October 2007 and April 2015.
According to The Telegraph, out of the entire group, over 1,000 children were admitted to hospital after catching the flu.
Researchers noted that, compared to first-born or only children, kids under six months who had one older sibling were twice as likely to be admitted. The risk tripled for those with two or more older siblings.
Rates of hospital admission for babies aged six to 23 months with older siblings were also higher, but the birth order association for this group was weaker.
Babies born during July and December were more likely to be hospitalised, also, as they are very young and more vulnerable at the start of the flu season.
Researchers say that a new nasal flu vaccine spray designed for children aged two to 16 could be very effective in combating the flu.
Lead scientist Dr Pia Hardelid, from UCL's Great Ormond Street Institute of Child Health, said: “Children are very effective spreaders of respiratory viruses like flu.
"Our study suggests that older siblings pose a risk of serious infection for their baby sisters and brothers.
"The nasal spray vaccine, which is now being offered in GP surgeries and primary schools in the UK, provides a good opportunity to protect the children who receive it, as well as their younger siblings."
She also urged pregnant mums to get the flu vaccine: “There is not much parents can do about the time of year their baby is born, but women can also help reduce the risk of serious flu for their newborns by taking up the invitation to have a vaccine when they are still pregnant."
If you have concerns about flu, always speak to a qualified medical professional.
